Vacuum device



W. KINTNER VACUUM DEVICE July 7, 1931.

Filed June 21, 1928 INVENTOR W. KIN

TNER BY ATTORNEY Patented July 7, 1931 UNITED STATES PATENT OFFICEWATSON KIN TNER, OF BLOOMFIELD, NEW JERSEY, ASSIGNOB TO WESTINGHOUSE MnCOMPANY, A CORPORATION OF PENNSYLVANIA VACUUM DEVICE Application filedJune 21,

This invention relates to the manufacture of incandescent electric lampsand relates more particularly to one of the component parts thereof andthe method for producing the same.

In the manufacture of incandescent electric lamps, radio tubes or otherelectrical vacuum devices including a sealed envelope, it is thepractice to employ an internal structure composed of a number ofconsolidated glass parts. For example, in an incandescent electric lampthe internal supporting structure, termed the stem, includes a reentranttube, termed a flare tube, which is sealed to the neck of the bulb, theflare tube in turn being consolidated with an exhaust tube and an arbor.These several parts are consolidated b fusing portions thereof toconstitute a glass mass and leading-in wires extend my thro igh the massand are sealed therein.

This mass is then compressed between suitable jaws and the resultantformation is termed a press. The press must necessarily have sufficientmaterial to effectively seal the leading-in wires and to provide aninternal bulbous cavity when air is directed down the exhaust tube whilethe mass is still plastic to provide an orifice between the exhaust tubeand the interior of the bulb. The said mass must also have suflicentstrength to withstand strains and prevent cracking.

It is important in the manufacture of an electrical device of thecharacter above described to economize wherever possible, both in theamount of labor expended and in the material employed, The developmentof high speed machines has tended to greatly reduce the labor factor andthe present invention aims to provide an internal structure for anelectrical vacuum device with the use of a minimum amount of materialWithout substantially changing the accepted standard structure.

In accomplisihng the above, the flare or reentrant tube which wasusually made of relatively thick wall tubing, in order to supplysuflicient material in the mass or press at the point of union betweenthe several parts, is in accordance with the present invention made ofrelatively thin wall. The

1928. Selfial No. 287,280.

required mass of material is-supplied by the disposition of a sufiicientamount of material, preferably in the form of an annulus of glass, whichis disposed within the end of the flare tube, which is subsequentlyheated for consolidation with the arbor and exhaust tube.

It is an object of the present invention, therefore, to provide a methodof producing a lamp stem with a minimum amount of ma terial.

Another object of the invention is to provide av lamp stem of thereentrant tube type in which the reentrant tube is provided with arelatively thin wall and additional material is supplied at the point ofconsolidation with t e other component parts of the stem.

Other objects and advantages of the invention will be evident from thefollowing description and the accompanying drawings, in which Figure 1shows the usual type of lamp stem as heretofore employed, partly insection;

Figure 2 is a side view of a flare or reentra-nt tube having arelatively thin wall;

Figure 3 is a side view of an annulus for supplying material to the endof the flare tu Figure 4 is a side view, partly in section, showing theseveral component parts of a stem in position to be consolidated inaccordance with the present invention; and

Figure 5 is a sectional view of a stem as employed for an electricaldevice such as a radio tube.

As shown in Figure 1 in the drawings, a lamp stem ordinarily includes anarbor 10, a flare or reentrant tube 11 and an exhaust tube 12, all ofwhich are consolidated in a press 13. Lead wires 14 and 15 extendthrough and are sealed in the press. Communication between the exhausttube and the interior of a bulb is provided through an aperture 16,which is formed in the press 13 while the material is in a plasticcondition.

As illustrated in Figures 2 to 4, a flare tube 17 is provided with arelatively thin wall, and a collar or annulus 18 havin a wallsufliciently thick to make up the 'fference in the material between therequired thick wallflare tube and the thin wall flare tube as provided.

A stem manufactured in accordance with the present invention may beassembled in the usual manner the flare tube 17 being properlypositioned, the collar 18 is, however, disposed adjacent to the lowerend of the flare tube which is disposed on a support rod 19. An arbor 20may be positioned in an aperture 21 provided in the rod 19, leading-inwires being properly positioned with their ends in pockets 22 providedat opposite sides of the aperture 21. An exhaust tube 23 may be held byjaws 24 in pro er relation to the annulus 18 and to an en of the arbor20. Jaws 25 may also be provided for holding the flare tube in position.

When the several parts are properly positioned, a fire 23 is directed toimpinge upon the outer wall of the flare tube adjacent to the annulus18, so that these parts may be heated and fused together so as to beconsolidated in a common mass, the annulus or collar 18 supplyingsuflicient material about the point of union between the parts, afterwhich jaws 26 and 27 are actuated to compress the plastic portion tomore firmly unite the parts in the so-called press.

While the material at the point of union between the parts is stillplastic, a jet of air is directed through exhaust tube 23 by means of anozzle 29 and a cavity, similar to the cavity 28 (shown in Figure 1) isformed and an aperture similar to aperture 16 (as shown in Figure 1) isproduced to' constitute an orifice at an end of the exhaust tube forexhausting purposes.

The various jaws for holding the parts, as well as the support memberfor holding spirit and scope of the invention asset forth in the ap ndedclaims.

What is claimed is:

1. The method of lproducing a stem for a. vacuum device whic consists indisposing a glass exhaust tube within a glass flare tube, positioning anannulus of glass withm the flare tube and around the exhaust tube and aplying heat to fuse said annulus and portions of said tubes into acommon mass.

2. The method of producing a stem for a vacuum device which consists indisposing a glass exhaust tube within a glass flare tube, positioning anannulus of glass within the flare tube and around the exhaust tube andapplying heat to fuse said annulus and portions of said tubes into acommon mass, and in directing a jet of air through said exhaust tubewhile said mass is still plastic, to provide an orifice at one end ofsaid exhaust tube.

In testimony whereof, I have hereunto subscribed my name this 20th dayof June, 1928.

WATSON KINTNER.

the arbor and the lead wires, are indicated more or lessdiagrammatically in the present drawings. It is obvious, however, thatany suitable type of stem making machine or stem head, as well known inthe lamp or radio tube making art, may be employed.

In the case of a radio tube stem, as shown in Figure 5, the reentranttube 30 and an exhaust tube 31 are employed but the arbor is omitted. Inthis case, support and lead wires 32 are embedded in the press andinasmuch as a relatively large number of support wires are necessary, ithas been desirable to use relatively heavy wall tubing for the flaretube to produce a large mass at the press. Thus the present invention isof particular advantage in connection with stems for radio tubes, aswell as for stems for other electrical vacuum devices.

By reason of the present invention, a considerable saving of material-is effected and the cost of production is materially reduced.

Although a preferred embodiment of the invention is shown and describedherein, it is to be understood that modifications may be made thereinwithout departing from the

